721  
FXUS65 KBYZ 102113  
AFDBYZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BILLINGS MT  
313 PM MDT SAT OCT 10 2026  
   
KEY MESSAGES  
 
 
- ADDITIONAL COLD FRONT MOVES THROUGH THIS EVENING AND OVERNIGHT  
WITH A FINAL PUSH SUNDAY NIGHT. MANY LOCATIONS COULD SEE THEIR  
FIRST FREEZE OF THE SEASON SUNDAY OR MONDAY MORNINGS.  
 
- STRONG WEATHER SYSTEM MOVES INTO REGION THIS WEEKEND. SNOW  
ACCUMULATION IS LIKELY THIS EVENING THROUGH MONDAY MORNING FOR  
SOUTH-CENTRAL MT MOUNTAINS AND FOOTHILLS, WITH RAIN AND WET  
SNOW AT LOWER ELEVATIONS.  
 
- WEATHER PATTERN REMAINS UNSETTLED THROUGH MID WEEK, WITH  
CONDITIONS GRADUALLY WARMING AND DRYING THROUGH LATE WEEK.  
 
 
   
DISCUSSION  
 
TODAY THROUGH FRIDAY...  
 
A LOW PRESSURE SYSTEM IS EXPECTED TO SLIDE THROUGH WESTERN MT AND  
TRACK SOUTH AND EAST THROUGH THE WEEK. TROPICAL MOISTURE BEING  
PULLED UP FROM HURRICANE RACHEL IS EXPECTED TO BOOST ATMOSPHERIC  
MOISTURE VALUES TO 150-250% OF NORMAL, GIVING WAY TO HIGH  
CONFIDENCE FOR APPRECIABLE PRECIPITATION ACROSS MUCH OF THE  
REGION, ESPECIALLY SOUTH-CENTRAL MT. A FRONTAL PASSAGE ASSOCIATED  
WITH THIS SYSTEM IS SET TO MOVE THROUGH THIS EVENING AND INTO THE  
OVERNIGHT HOURS BRINGING COOL AND WET CONDITIONS. HIGH CONFIDENCE  
EXISTS FOR LOCATIONS OF YELLOWSTONE COUNTY WEST TO RECEIVE AN  
INCH OF LIQUID PRECIPITATION WITH THIS EVENT. THE EASTWARD EXTENT  
OF THE COOL AIR IS EXPECTED TO GET INTO BILLINGS AND SURROUNDING  
AREAS SUNDAY EVENING INTO MONDAY MORNING, LEAVING THAT TIME TO BE  
THE BEST TIME FOR RAIN/SNOW MIX. CHANGES TO THE FORECAST/PRODUCTS  
INCLUDE AN UPGRADE TO WINTER STORM WARNING STARTING AT 6PM MDT  
THIS EVENING DUE TO INCREASED CONCERN FOR HIGHER SNOW AMOUNTS  
(NEAR ONE FOOT IN HIGHER TERRAIN) AND BLOWING SNOW IN THE JUDITH  
GAP AREA FROM GUSTY NORTH WINDS. ADDITIONALLY, GOLDEN VALLEY,  
MUSSELSHELL AND NORTHERN STILLWATER COUNTIES WERE ADDED AS  
WINTER WEATHER ADVISORIES SUNDAY EVENING THROUGH MONDAY MORNING  
FOR UP TO 4 INCHES OF SNOW. USE CAUTION IF TRAVELING ALONG I-90  
AND US-191 THROUGH MONDAY AND CHECK ROAD AND WEATHER CONDITIONS  
BEFORE TRAVELING.  
 
HIGHER HEIGHTS BEGIN TO MOVE IN TUESDAY, BUT AS THE LOW MOVES  
THROUGH WY, LOW TO MODERATE PRECIPITATION CHANCES REMAIN IN THE  
FORECAST FOR LOCATIONS ALONG THE MT/WY BORDER. ALTHOUGH THE UPPER  
LEVEL PATTERN DIFFERS AMONGST ENSEMBLES IN THE LONG TERM, BOTH  
PATTERNS INDICATE WARMER AND DRY CONDITIONS FOR THE END OF THE  
WEEK.  
 
HIGH TEMPERATURES WILL RANGE FROM THE 30S TO LOW 50S SUNDAY AND  
MONDAY, WITH MANY LOCATIONS SEEING THEIR FIRST FREEZE OF THE YEAR  
SUNDAY AND MONDAY MORNINGS. TEMPERATURES WILL BEGIN TO REBOUND  
INTO THE 40S AND 50S TUESDAY AND WEDNESDAY, INCREASING INTO THE  
60S BY THE END OF THE WEEK. TS  
 
   
AVIATION  
 
ISOLATED SHOWERS WILL MOVE OVER THE AREA FROM THE SOUTHWEST TO  
NORTHEAST THROUGH THE AFTERNOON AS A LARGE DISTURBANCE BEGINS  
MOVING INTO THE REGION. A COLD FRONT WILL DROP THROUGH THE AREA  
FROM NORTH TO SOUTH THIS AFTERNOON AND EVENING. EXPECT INCREASED  
SHOWER ACTIVITY ALONG THE FRONT AS IT MOVES THROUGH, AND AN  
ISOLATED THUNDERSTORM CAN'T BE RULED OUT. PRECIPITATION BECOMES  
MORE WIDESPREAD OVER THE WESTERN FOOTHILLS THIS EVENING WITH GUSTY  
EASTERLY WINDS. LOCALLY HEAVY SHOWERS ARE POSSIBLE PRODUCING IFR  
CONDITIONS. AFTER 06Z, EXPECT PRECIPITATION TO BECOME A  
PERSISTENT RAIN OVER THE WESTERN HALF OF THE FORECAST AREA  
(KBIL/KSHR/KLVM) RESULTING IN PREDOMINANTLY MVFR TO IFR CONDITIONS  
OVERNIGHT. SNOW LEVELS DROP UNDER 6KFT AGL FOR THE WESTERN  
MOUNTAINS AND FOOTHILLS BY SUNRISE SUNDAY MORNING. PERIODS OF  
RAIN/SNOW WILL MOVE OVER THE AREA FOR SUNDAY. MOUNTAINS WILL BE  
OBSCURED AT TIMES THROUGH THE PERIOD. STP  
 
 
   
PRELIMINARY POINT TEMP/POPS  
 
SUN MON TUE WED THU FRI SAT  
-----------------------------------------------------------  
BIL 037/042 032/042 031/051 035/057 040/060 037/060 041/070  
++/O +8/O 11/B 11/B 21/B 10/U 00/U  
LVM 030/038 026/043 025/053 027/057 030/060 029/064 034/072  
++/O +6/O 01/B 01/U 12/W 10/U 00/U  
HDN 038/047 033/045 030/054 034/059 036/061 032/062 032/072  
99/R +8/R 11/B 12/W 21/B 11/U 00/U  
MLS 040/048 035/044 035/052 036/057 040/059 035/057 037/068  
69/R 99/R 11/B 12/W 21/B 11/U 00/U  
4BQ 043/051 040/048 037/054 039/058 041/059 037/058 039/070  
36/R 86/R 12/R 23/W 32/W 11/U 10/U  
BHK 035/050 030/046 031/054 033/059 035/060 031/058 032/068  
58/R 98/R 11/B 12/W 32/W 21/B 00/U  
SHR 037/049 033/047 030/054 033/057 035/059 031/061 033/072  
77/R 94/R 23/R 44/W 44/W 21/U 00/U  
 
 
   
BYZ WATCHES/WARNINGS/ADVISORIES  
 
MT...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM SUNDAY TO NOON  
MDT MONDAY FOR ZONES 29-34-42.  
WINTER WEATHER ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO  
NOON MDT MONDAY FOR ZONES 40-65-66-141-228.  
WINTER STORM WARNING IN EFFECT UNTIL NOON MDT MONDAY FOR  
ZONES 63-67-68.  
WINTER STORM WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO NOON  
MDT MONDAY FOR ZONE 172.  
WY...NONE.  
 
 
 
 
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